During which time frame was most of the asbestos installed in buildings in the United States?

The period from the 1950s to the 1970s marks the peak of asbestos use in construction throughout the United States. During this time, asbestos was widely recognized for its fire-resistant properties and was used extensively in various building materials, including insulation, floor tiles, and roofing products. This surge in usage can be attributed to a combination of industrial growth and a lack of understanding regarding the health hazards associated with asbestos.

As regulations and awareness of asbestos-related health risks began to surface in the late 1970s, the use of asbestos started to decline significantly. Dental and construction industries gradually transitioned to safer alternatives, but the legacy of the asbestos already used remains a concern in many older buildings. Thus, the 1950s to 1970s is accurately identified as the era when most asbestos was installed, making it the correct answer to the question.